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Migration/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby A boy, Tim, and a robot, Moby, are walking through an autumn forest. A large flock of birds flies overhead. TIM: Whoa. Moby hides under a fallen tree. TIM: Come out of there, you coward. Moby hands Tim a sheet of paper. Tim reads from the typed letter. TIM: Dear Tim and Moby, why do animals migrate? From, Hubert. TIM: Migration is the instinctive movement of a group of animals. Animals usually migrate for any of three reasons, to find more food, to reach a better climate, or to ensure reproduction. Images show a plant, the sun, and an egg. TIM: Most migrations are seasonal, meaning they happen every year at certain times. The journeys animals take can be extremely long. An animation shows a map of North America, a hummingbird flying north and south, and changing calendar pages denoting the passing of time. TIM: Some birds fly thousands of kilometers on their migrations, nonstop. MOBY: Beep. TIM: Yeah, and they do it every year of their lives. It makes sense. Seasonal changes can have huge effects on animals. Shifts in weather can affect food supplies. An image shows a reindeer on a tundra. Snow is covering parts of the ground. TIM: And make it tougher for newborn animals to survive. An animation shows a bird in a nest during a blizzard. The bird is shivering. MOBY: Beep. TIM: Yeah, you could say that migration is a way for animals to keep their environments stable and friendly. Migrations aren't always controlled by the seasons, though. Some animals migrate on a nomadic, or unpredictable, schedule. Elephants in Mali, Africa can hear rainstorms from very far away and travel quickly to meet them. An animation shows a herd of elephants hearing a rainstorm and acting as Tim describes. TIM: And some animals, like locusts, follow one-way, or removal, migrations. They move from place to place until the food supply runs out, rarely hitting the same place twice. An animation shows a swarm of locusts flying over a town. TIM: Animals use all kinds of guides to know how to get where they're going, wind patterns, currents in the water, and even geographic landmarks. Images represent the wind, a water current, and a mountain. TIM: Some use more specialized methods. Certain migratory birds have tiny particles of the magnetic mineral magnetite in their brains. An animation shows a flying bird. Radiating lines represent a magnetic field centered on the bird's head. TIM: It's thought that these particles allow the birds to use Earth's magnetic field to find their way. A second animation shows the earth from space. Magnetic lines radiate from Earth in a similar way as they do from the bird's head. TIM: And animals are amazingly sensitive to changes in season. They have internal clocks that let them know what time of year it is. MOBY: Beep. Moby pictures a bird's nest containing a mother bird and an alarm clock. TIM: No, it's not an actual clock. But the amount of sunlight, the temperature, and their own internal chemistry can give animals a good idea of when to start moving. By the way, humans have a history of migration, too. It's thought that our species originated in Africa, then migrated over thousands of years to populate the rest of the planet. An animated world map represents human origins in Africa and, using arrows, illustrates human migration to Europe, Asia, and elsewhere. TIM: Speaking of which, we better migrate back home. I have to feed on some dinner. Moby looks embarrassed. Tim smiles awkwardly.Category:BrainPOP Transcripts Category:BrainPOP Science Transcripts